The two graphs show the main sources of energy in the USA in the 1980s and the 1990s.

The charts compare changes in the share of sources of energy in United States in two different decades . Generally , while tow experienced rises , there were declines in the two .

According to the diagrams , oil accounted for the most significant proportion in 1980 ( 42 % ) while it had a considerable decrease ( 9 % ) over 10 years . The contribution of natural gas approximately remained constant ( only 1 % ) as well as hydroelectric power at an insignificant { humble } level . Whereas nuclear power had a substantial growth which doubled from 5 % to 10 % .There was a 5 % rise in coal contribution , which climbed 22 % to 27 % .

Overall , oil contributed the largest proportion of source of energy throughout the survey , however hydroelectric power had the smallest share .
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My friends this essay is too short but i want to know about grammatical mistakes . Thanks all .

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in the United States


.... The two words I have highlighted tend to give a different impression about the charts. For me, I think that each pie chart shows the energy source used by each year. So, together they present a comparison. You better rephrase this sentence to give a clear idea to the reader about what these pie charts present. Also, it is good to mention the type of chart too;

The two pie charts illustrate the percentage usage of energy sources in the United State in 1980 and 1990 respectively.